Arrays of light sensing pixels are widely used in digital camera sensors, which are incorporated into devices such as automobiles and smartphones. In some applications, such a digital camera sensor may be instructed to acquire images, and the field of view represented by those images may include lighting delivered by light emitting diodes (LEDs).
LEDs typically operate by emitting discrete pulses of light in accordance with a duty cycle. This may create an issue with properly representing the shape and color of the light emitted by the LEDs, if the acquisition time of the digital camera sensor is not synchronized with the duty cycle of the LEDs. That is, a LED may be in an “off” portion of its duty cycle while the digital camera sensor is acquiring an image, or may be transitioning between “off” and “on”, or between “on” and “off”, while the digital camera sensor is acquiring the image.
This can be particularly problematic in cases where another electronic device relies upon images captured by a digital camera sensor in taking other actions. For example, in certain automotive applications, a vehicle may autonomously take an action based upon an illuminated color of a traffic light captured by a digital image sensor, or may present information to a driver based upon the illuminated color of the traffic light. Since an issue with the image captured by the digital camera sensor may thus result in an incorrect autonomous action or in incorrect information being presented to the user, there is a strong commercial desire for improved light sensing pixels capable of properly representing light from emitted LEDs.